(19)
(11) EP 0 425 179 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
01.04.1992 Bulletin 1992/14

(43) Date of publication A2:
02.05.1991 Bulletin 1991/18

(21) Application number: 90311374.4

(22) Date of filing: 17.10.1990
(51) International Patent Classification (IPC)5: G06F 3/033
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 23.10.1989 US 425777

(71) Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
Armonk, NY 10504 (US)

(72) Inventors:
  • Corona, James
    Kingston, New York 12401 (US)
  • Gibbons, Daniel Gerard
    Ulster Park, New York 12487 (US)
  • Lindgren, Terence Wellace
    Littleton, Massachusetts 01460 (US)

(74) Representative: Burt, Roger James, Dr. et al
IBM United Kingdom Limited Intellectual Property Department Hursley Park
Winchester Hampshire SO21 2JN
Winchester Hampshire SO21 2JN (GB)


(56) References cited: : 
   
       


    (54) Object selection detection in a graphics display system


    (57) A method and apparatus for detecting operator selection of a graphics object prior to rasterization and pixel generation for that object. The method divides screen into regions and analyzes successive end points and vectors based upon their region to determine trivial picks and trivial no picks. Non-trivial conditions are analyzed by evaluating the slope of the line through a test of sample lines drawn through pick window vertices. Apparatus for implementing pick detect is provided that accomplishes pick detect as part of graphics pipeline processing. In the trivial pick or no pick cases, the apparatus does not slow pipeline operation, while in a non-trivial case, extra processing cycles are required.







    Search report